Fair Value Measurements - Schedule of Company's Financial Instruments (Detail) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Fair Value [Member]
Financial assets:
Cash and cash equivalents, including restricted cash		$ 54.2	$ 32.3
Investments and other assets	[1]	1.2	1.2
Financial liabilities:
Total debt		950.9	896.2
Carrying Value [Member]
Financial assets:
Cash and cash equivalents, including restricted cash		54.2	32.3
Investments and other assets	[1]	1.2	1.2
Financial liabilities:
Total debt		$ 963.4	$ 911.9

[1] Excludes equity method investments.